Coral Island x FunGuys Swarm Crossover items not showing in joined Co-Op Session

[twin crane]

Platform: Steam

As seen in the attached screenshot, I successfully claimed the crossover items.

They show up when I'm loading in a singleplayer game.
They also show up when I'm hosting a co-op game.
They don't show up, however, when I'm joining a co-op game. (In the mailbox)

My girlfriend claimed the crossover reward as well and she, being the host, got the reward mail in her mailbox and is able to use the items without issue.
Since she claimed the reward, I am able to craft the chest, but nothing else showed up.

We tried the same with her joining my hosted game and the issue is the exact same but in reverse, with her not recieving the rewards.

I'm unsure if this is a bug or intended design that only the host recieves the mail and the attached items, but thought I'd just drop this here.

[winged pawn]

first, any MP issues should be reported here #1405384975137898524
second, if your friend as a host has claimed items, guests can have them by purchasing blueprints at the monkey shop

[twin crane]

Very interesting design choice, but thank you for clearing it up!

[desert grail]

Hello @twin crane, thank you for your report, and yup if you run into any multiplayer-related issues in the future, post them in the channel @winged pawn (thanks for the help!) shared above so we can assist you more efficiently